Are most/all flights affected by a noticeable amount of turbulence?

How common is turbulence that is severe enough to feel uncomfortable? I don't mean a little shaking here and there, but a drop that lasts a second or two.

Last 2 flights I was on (Paris to Singapore, and Singapore to Sydney) had more than one big drop of turbulence, to the point where passengers screamed.

Is this common? I know it is relatively safe, but feel uneasy about flying again as it was uncomfortable and scary!

• Possible duplicate of How dangerous was the turbulence on this commercial flight? – Simon Dec 9 '15 at 11:15
• @Simon, I am not sure this is a duplicate. That question is about how to rate severity and how dangerous it is, this one is how common it is. – Jan Hudec Dec 9 '15 at 17:37
• I'm not worried about the dangerous. I want to know how common it is – Barney Chambers Dec 10 '15 at 7:31
• Well in that case, the question is asking for opinions. severe enough to feel uncomfortable. I don't mind turbulence at all and I've been in some very rough stuff and often experience drops that "last a second or two". I simply don't feel uncomfortable in so you need an empirical measure to ask how common it is. E.g. I can't remember being on a flight that didn't have some turbulence. Maybe someone on the flight felt uncomfortable whilst I just enjoyed the ride. Perhaps if you changed the question to ask "how common is moderate turbulence", since moderate has a defined meaning. – Simon Dec 10 '15 at 7:56
• It's severe and frequent enough, and planned such certain to become worse with climate change, to see investments in research for better prediction and detection. These two studies were cited in this article in the Guardian. To get a specific figure, you probably need to restrict your question to a type of route (land or ocean) and a geographical area. – mins Dec 10 '15 at 11:09

It's very difficult to answer this question as it depends upon so many different things: - Location - Time of day - Season - Flight level - Terrain below - Current weather (of course) - Type of aircraft - The crew and their knowledge / weather radar use.

What also makes it hard is that what 'feels uncomfortable' for one person might not for another.

In the tropics it's quite common for flights to be affected by turbulence. Most will see at least some light chop. In my experience of a few hundred long-haul flights through the tropics I've only had a couple with no moderate turbulence (what you might call uncomfortable). In a similar number of short-haul flights in Europe I'd say that around 50% had no significant turbulence at all and only around 5% had moderate turbulence.

You're more likely to experience turbulence in the tropics as there's a lot more convective activity there (air rising and falling). Away from the tropics the USA tends to generate turbulence whilst Europe does not (relatively speaking). SE Asia is particularly well known for turbulence encounters.

• This is a fantastic answer, thank you – Barney Chambers Dec 24 '15 at 17:59

Clear air turbulence (CAT) is associated with jet streams. Depending on the region, and even the season, CAT is common, and it can't be identified by weather radar, but the crew usually studies the weather chart before the flight, and can receive pieces of information from ground units, ATCOs and for aircraft leading them. So, most of the times, they can be aware of CAT, but it can also disrupt the flights, as you could feel during your journeys.

• how common is 'common'? Every flight? Every 1 in 5 flights? And is CAT always severe (in terms of making people vomit and scream) – Barney Chambers Dec 10 '15 at 7:33
• CAT is rarely severe. In the vast (>90%) majority of cases it's minor. There's only a handful of cases each year (out of all flights worldwide) where CAT is severe enough to cause vomiting, people being thrown around, etc). In my experience most "severe CAT" cases aren't really CAT at all, but a crew not noticing nearby weather. – os1 Dec 11 '15 at 6:57